Accomplishments during the year: 1. The sialic acid binding site has been modeled for BAEBL, identifying requirements for sialic acid binding. 2. The immune response to RH4 has been studied. This work continues to expand our understanding of parasite invasion of red cells by identifying the receptors and ligands and determining the potential of these targets for vaccine development. We show that recombinant P. falciparum RH 4 can block invasion but antibodies to PfRH4 cannot block invasion. 3. Begun to study viable merozoites during invasion to follow the moving junction and the effect of anti-AMA1 on invasion. 4. Study the changes in the histone modifications of nucleosomes of RH4 and PEBL to correlate with the change of expression in Dd2 to Dd2/nm. 5. Begun to study the cytoplasmic domains of molecules in the moving junction to determine if they bind to aldolase or other molecules that bind actin. 5. Study the role of RH1 and RH2 as targets for vaccine development.